1. Field of the Invention
The present invention relates to a system for splitting and spreading existing underground utility pipe and pipe fittings and pulling new pipe through the bore of the utility pipe and pipe fittings.
2. Description of the Background Art
Throughout the United States steps are being taken to improve methods of replacing existing underground utility pipe and pipe fittings. In many municipalities, the utility pipes have been installed long ago and must be replaced on a regular scheduled basis to maintain vital utility services to its customers. Also, where rapid growth has occurred, the utility pipes are now undersized with respect to the desired capacity and must be replaced with larger capacity pipe. Initial replacement methods involved excavating the entire length of pipe and replacing it with new pipe in the excavated trench. This was very expensive and time consuming. Further, other vital utility services (telephone, electric) were also disrupted because the conduits carrying those services were usually in the same trench.
Trenchless replacement of utility pipe initially focused on slipping smaller diameter pipe through the bore of the utility pipe. This reduced the installation time and expense dramatically. However, the smaller diameter slipped pipe also reduced the utility system capacity. This is unacceptable to most municipalities.
U.S. Pat. No. 2,983,042 issued to Frantz et al. discloses a tube splitting apparatus having a plurality of cutter wheels for cutting a tube (pipe) that is stuck in a sleeve into two halves. The cutter wheels shape the edge of the split halves inwardly. U.S. Pat. No. '042 teaches away from only one path for the cutter wheels to traverse. Further, U.S. Pat. No. '042 is silent on scoring and cutting the utility pipe fittings.
U.S. Pat. No. 1,001,205 issued to Lovell discloses a well casing splitter and perforator for admitting water or oil through a group of slits into the casing. U.S. Pat. No. '205 teaches away from making a continuous cut through the pipe. U.S. Pat. No. '205 is silent on scoring and cutting the utility pipe fittings.
U.S. Pat. No. 4,106,561 issued to Jerome et al. discloses a well casing perforator adapted for use with pneumatically powered rotary drilling equipment commonly found in the oil exploration field. U.S. Pat. No. '561 teaches the intermittent engagement of a cam shaped perforating wheel with the well casing. U.S. Pat. No. '561 teaches away from a plurality of circular cutting wheels in continuous engagement with the interior of the utility pipe wall. Further, U.S. Pat. No. '561 teaches away from hydraulic means to pull the cutter assembly through the bore of the underground utility pipe and pipe fittings.
U.S. Pat. No. 3,181,302 issued to Lindsay discloses a pipe splitter and spreader that cuts the existing pipe into two halves and spreads the halves apart. U.S. Pat. No. '302 teaches away from a plurality of cutter wheels making only one cut in the existing pipe and maintaining the cut pipe as one whole pipe, even after the cut is made. U.S. Pat. No. '302 teaches away from equal diameter cutter wheels. U.S. Pat. No. 5,171,106 issued to Rockower et al. discloses a cutting tool having a plurality of cutter wheels of unequal diameter. U.S. Pat. No. '106 also discloses a pair of guide rollers for rotational engagement with the interior wall of the pipe. U.S. Pat. No. '106 teaches away from equal diameter cutter wheels and further teaches away from a plurality of paired pipe expanders to loosen and scrape built-up debris from the interior wall of the existing pipe and pipe fittings.
U.S. Pat. No. 4,455,107 issued to Schosek discloses a hydraulic apparatus for forcing a rod through undisturbed earth with axial force exerted through a set of jaws. U.S. Pat. No. '107 teaches the installation of new plastic pipe only in the bore created by the rod traversing the undisturbed soil. U.S. Pat. No. '107 teaches away from a plurality of rods forming a train. U.S. Pat. No. '107 is silent on replacing existing utility pipe and pipe fittings.
U.S. Pat. No. 4,903,406 issued to Schosek et al. teaches the use of a pipe splitter apparatus having a single cutting wheel having a circular diameter greater than the bore of the pipe to be split. U.S. Pat. No. '406 teaches the use of side wheels to rotatably engage the interior wall of the pipe. U.S. Pat. No. '406 teaches away from a plurality of cutter wheels.
None of these previous efforts, however, provide the benefits intended with the present invention. Additionally, prior techniques do not suggest, the present inventive combination of component elements as disclosed and claimed herein. The present invention achieves its intended purposes, objectives and advantages over the prior art devices through a new, useful and unobvious combination of component elements, which is simple to use, with the utilization of a minimum number of functioning parts, at a reasonable cost to manufacture, assemble, test and by employing only readily available material.
Therefore, it is an object of the present invention to provide a trenchless system to replace existing worn out utility pipe and pipe fittings with new pipe of equal or greater diameter.
It is a further object to provide a system to cut the pipe and the pipe fittings along a continuous longitudinal line on an upper hemispheric section of the pipe and pipe fittings.
It is another object of the invention to provide a pipe cutting system that maintains its vertical orientation through the entire traverse of the existing pipe to be replaced.
It is yet another object of the invention to provide a system that has equal diameter cutter wheels to minimize the inventory of cutter wheels in the field.
It is still another object of the invention to provide a system that loosens and scrapes built up debris from the interior wall of the existing pipe and pipe fittings as the cut is made.
It is yet another object of the invention to provide a hydraulic apparatus that can force a rod through undisturbed earth using only axial forces through a set of split jaws.
It is yet another object of the invention to provide a system that requires only two men to operate in the field.
It is still yet another object of the invention to provide a pipe spreading and splitting system that does not separate the existing pipe into two equal sized sections.
It is another object of the invention to provide a pipe splitting and spreading system that works equally well with either plastic or steel walled pipe.
It is yet another object of the invention to provide a pipe splitting and spreading system which operates with a minimum of force necessary to propel the invention through the existing pipe and pipe fittings and to ensure that the existing pipe and pipe fittings remain in place during the splitting/spreading process.
It is another object of the invention to provide a pipe splitting and spreading system which forms a single longitudinal cut along a longitudinal path of the pipe and pipe fittings to be split.
A final object of this invention to be specifically enumerated herein is to provide a pipe splitting and spreading system in accordance with the proceeding objects and which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that would be economically feasible, long lasting and relatively trouble free in operation.
Although there have been many inventions related to pipe splitting and spreading systems, none of the inventions have become sufficiently compact, low cost and reliable enough to become commonly used. The present invention meets the requirements of the simplified design, compact size, low initial cost, low operating cost, ease of installation and maintainability, and minimal amount of training to successfully employ the invention.
The foregoing has outlined the more pertinent objects of the invention. These objects should be construed to be merely illustrative of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiments in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.